Abstract

Single-point thermometry, or the measurement of localized temperature changes, is a key technique for characterizing the physical, chemical, and biological process at a specific biological site, especially for a medium that can be heated up by a highly focused laser beam. Herein, we report on the development of a technique for the nondestructive local temperature measurement of optically irradiated biological membranes, based on fluorescence from an environmentally sensitive dye¹ in an organically engineered liposome.² An optical multichannel analyzer (OMA) is combined with a microscope to measure spectral fluorescence (see Fig. 1) to offer a high temperature sensitivity, submicron spatial resolution, high speed, and large signal-to-noise (S/N) ratio. In addition, this technique is nondestructive. The most sensitive temperature regime for this measurement is in the vicinity of the phase transition temperature of the liposome, which depends on its membrane molecular structure. Using this technique the temperature in a micrometer region has been measured, with a 0.1°C sensitivity.

© 1994 IEEE